Interlocking stair-form.



N. Bois. l INTRLOCKING STAIR FORNI.

APPLICATION FILED AUG.27. 1914.

Patented Oct. 23, 1917.

2 SHEETS-SHEET l.

N. BOIS.

INTERLOCKING STAIR FORM.

APPLICATION FILED Auaz. |914.

Mfj.. Patented 06u23, 1917.

2 SHEETS-SHEET 2.

` .IIIIIIII Isifi l A I |,I I Y IIIIIIIII.

f III I IIIII lIIIII" 5 iM/ewig? ift tren srirns rn'rnnr ernten Y n nrneninn ners, or SAN rnnnoisoo, cerimoniale,

To aZZ inkom t mag/concern:

Be it' known that I, NATHANIEL Bois, e

citizen of the United States, residing` in the arranged tovinterloclr with the stair forms i :adjoining it; seeond, to 'provide ,2t nosing of :i double thickness for each tread for strengthening purposes; third, to provide 'e nosinp; arranged to rigidly engage the top oi? the riser of the steir below it; fourth, to `provide u' stair form having a'pocket'in the tread and lower 7portion of the riser for the reception of concrete; iifth, to-provide n concrete .tread that 'shall extend into the riser so es to form a round sanitary corner und also forni a wearing?,` surface for u portion of the said riser, and sixth, to eliminate the necessity for bolts, rods nuts and the like.

accomplish these several features by means of the device disclosed in the drawings forming a part of the present specification wherein like characters of reference ere used to designate similar parts throughout the seid specification und drawings, and in which- Figure i is fr perspective view, partly in section, disclosing the general forni und ar# rangement `of the stair forms secured to- Fig; $3 is :in enlarged broken sectional ,view one oi the stair forms and a portion ot euch adjacent form, disclosing' the pocket orvthe concrete tread and the manner in;

y which the nosinr; of the stair above interi4 Fig. 5vis e sectional view of e modiedi Specification of Letters Patent. nppncanon inea Auguste?, 1914.

Patented Giet.. 23, 193i?. serial No. #i5-9,266.

form of stair form whereinthe nosings are formed semicirculur, and v Fig. 6 is 'a detailed View of the seniicircular nosings disclosing thel manner in which onesemicirculur nosing is inserted and interlocked within the other.

The numeral l is used to designate the stringers to which are fastened the angle irons 2 for the support of the stair forms. The stair forinseomprise e tread 3 having anupturned channel l on the 'iront edges thereof.. so as to form. o suitable nosing. The risers 5 ere formed ,integral with the trend 3 and havev the upper portions thereof slightly otiset toward-the front of the treed .3, the lower nortion 5, of the seid odset portion being slightly above thetop oi' the. nosing 4 formed in the iront edge of the tread ln this manner a 'pocket is formed for the reception of concrete, which pocket will give a lconcrete treed 7 havingA a lateral e2:- tension 8 et the rear end thereof, seid eX# tension 8 forming' the-lower portion of the i riser, which construction will also. permit of a sanitary curved corner 9 t'o be formed therein. The curved sanitary corner 9 will also produce a greeterstrength between. the concrete tread i' and the extension 8 thereto and 'thereby strengthen the junction of the seid tread 7 and the extension 8 thereof. The top of the riser 5 has ormedfthereon a ehannel() havin the back thereof turned toward the front ci?? the tread 3.

A depending flange 12 on the beck portion of the said channel l0 at 5,' forms e nosing-in conjunction with the seid channel 10, which is arranged to surf round and engage the nosingfiA of the tread 3 on a similar stair forrn above it. Sirnilerly,vthe nosing 6L on the (front edge oftheV treed 3 is engaged by the channel 10 und d`ethe ter: of the riser Ipending ienge l formed on the riser 5 on. y

the stair form below it. n this manner the stair forms are interlool, ed und rigidly secured to eechother, .so/that after the concrete isset in the pocket ofthe treed it will be impossible to disengage .one stair form from anotherfwitho'ut'idestroying thcA stair y form. j A further advantage-is that the nosing is formed of af double thiclme of material which will thereby impart greater strength to the front of each treed, which is subjectiod to the greatest amount of weer,

' of the said tread 5 y"Elie lower portion of the riser 5 being offset so as to accommodate its surface to the front surface of the egnorete extension 8, it can oe readily seen that the lower portion which is exposed to the greatest wear will be composed of a heavier andl more durable material, thereby entending the life of each. riser.

In Figs. 5- and 6, l have illustrated a modiied form wherein the nosings are formed of semieirenlar ohannelsfor purposes of appearances. lin this form there. will he no slm-arp4 edge of the nosing exposed to wear and the depending flange 14E on the edge of the seniioirenlar channel 10 will engage the semioireular nosing 4" of the tread 3 in the manner heretofore described for the pre ferred form of the invention.

in Fig. 6 li have illustrated the manner in which the curved nosing 4C of the tread 3 may be inserted into theeurved channel'lO ofthe riser 5. y

lit is obvious from the foregoing that li have provided an improved stair form wherein-each unit is formed with an oEset riser integral with theytead and having a i'iosing also formed integral therewith and arranged to interlock with thelnosing on. the tread of a similar stair aloove it.

s'aving thus deeerihed my invention what claim. as new an'L desire to secure by Let-v ters Patent ier The combination with a stair form having a tread, a riser connected thereto, and a rearwardly facing; channel formed on the upper edge, said channel comprising a bottom wall, a top wall and a forward side Wall, and a depending flange formed on the rear edge of the top wall, of a second stair form having a tread, and a nosing formed on the forward edge thereof, said nosing comprising an up standing wail and rearwardly extending wall on the upper edge of the last mentioned wall5 the forward portion of the treadtjorojeoting1 into said channel in Contact with the bottom wall 'thereof and the nosing fitting within the channel in continuous Contact with the side wall and top wall thereof, the depending iiange extending below the plane of the top wall of the nosing.

.in vwiti'iees whereof ll4 hereunto set my signature in the presence of two Subscribing witnesses.

NATHANEL BUT-Q 

